Be sure to ask for quotes not only from your current bank or any other nearby, but also from other finance companies, and online lenders as well. Make sure the lenders you enquire from aren't looking up your credit rating unless you're ready to proceed with them alone. Any more than four credit checks in one month looks suspect, and may affect your credit rating. Ask if they're going to check your credit-rating first, to be on the safe side.
You will be surprised to find that loans offered by online money-lending companies are often more convenient and with less restrictive conditions than those offered by banks. This is because banks earn money by a number of different means, as opposed to online lenders, whose primary income is a direct result of the amount of money they lend.

Depending on how bad your credit history is, it may be very difficult to find unsecured loans, as most lenders will impose very high rates, and others will simply reject your application.
Although it is still possible to find convenient low-rated unsecured or bad credit loans, the chances of that are very small. The smartest choice is to look for a secured loan instead; there are a lot of lenders willing to offer you bad credit loans at low rates if you have any collateral to offer them as a warranty of payback. Depending on the amount of money you are borrowing, lenders will take your car or house as security and happily allow you to get your loan.
Have in mind that it is always better to pay back the money you borrowed as soon as you are able to.

Try to choose among those loans that allow you to make early payments; the quicker you pay back, the less interest you pay. On the other hand, if you extend the duration of the loan, you will have to pay much more money in interest.
Although you may not actually take out a loan, it will be shown in your record and may look very bad on your history when applying for another in the future, so limit yourself to asking for quotes and apply only for that loan offer you consider to be the best. If your application gets rejected, however, you may move on to the next best offer on your list.
In your research it's advisable to review if the provider is a member of the Finance Industry Standards Association (FISA), which follows the confidentiality guidelines set out for this association, and also those providers registered under the Data Protection Act (DPA) who adhere to the letter of the law from the Data Protection Register.